# PlatonicSolids

VTKExamples/Cxx/GeometricObjects/PlatonicSolids

### Description¶

Display all five Platonic solids in a grid.

Platonic solids are regular, convex polyhedrons. They are constructed by congruent (identical in shape and size) regular (all angles equal and all sides equal) polygonal faces with the same number of faces meeting at each vertex.

Five solids satisfy the above criteria:

Figure Tetrahedron Cube Octahedron Icosahedron Dodecahedron
Vertices 4 8 6 (2 × 3) 12 (4 × 3) 20 (8 + 4 × 3)
Edges 6 12 12 30 30
Faces 4 6 8 20 12

The relationship between vertices, edges and faces is given by Euler's formula:

V - E + F = 2


Other Languages

See (Python)

Question

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### Code¶

PlatonicSolids.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkLookupTable.h>
#include <vtkNamedColors.h>
#include <vtkPlatonicSolidSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkTextActor.h>
#include <vtkTextMapper.h>
#include <vtkTextProperty.h>

#include <string>
#include <vector>

int main(int, char* [])
{
vtkSmartPointer<vtkNamedColors> colors =
vtkSmartPointer<vtkNamedColors>::New();

// Each face has a different cell scalar
// Here we create a lookup table with a different colour
// for each face. The colors have been carefully
// chosen so that adjacent cells are colored distinctly.
vtkSmartPointer<vtkLookupTable> lut =
vtkSmartPointer<vtkLookupTable>::New();
lut->SetNumberOfTableValues(20);
lut->SetTableRange(0.0, 19.0);
lut->Build();
lut->SetTableValue(0, 0.1, 0.1, 0.1);
lut->SetTableValue(1, 0, 0, 1);
lut->SetTableValue(2, 0, 1, 0);
lut->SetTableValue(3, 0, 1, 1);
lut->SetTableValue(4, 1, 0, 0);
lut->SetTableValue(5, 1, 0, 1);
lut->SetTableValue(6, 1, 1, 0);
lut->SetTableValue(7, 0.9, 0.7, 0.9);
lut->SetTableValue(8, 0.5, 0.5, 0.5);
lut->SetTableValue(9, 0.0, 0.0, 0.7);
lut->SetTableValue(10, 0.5, 0.7, 0.5);
lut->SetTableValue(11, 0, 0.7, 0.7);
lut->SetTableValue(12, 0.7, 0, 0);
lut->SetTableValue(13, 0.7, 0, 0.7);
lut->SetTableValue(14, 0.7, 0.7, 0);
lut->SetTableValue(15, 0, 0, 0.4);
lut->SetTableValue(16, 0, 0.4, 0);
lut->SetTableValue(17, 0, 0.4, 0.4);
lut->SetTableValue(18, 0.4, 0, 0);
lut->SetTableValue(19, 0.4, 0, 0.4);

std::vector<vtkSmartPointer<vtkPolyDataMapper>> mappers;
std::vector<vtkSmartPointer<vtkActor>> actors;
std::vector<vtkSmartPointer<vtkTextMapper>> textMappers;
std::vector<vtkSmartPointer<vtkActor2D>> textActors;
std::vector<vtkSmartPointer<vtkRenderer>> renderers;

// Create a common text property.
vtkSmartPointer<vtkTextProperty> textProperty =
vtkSmartPointer<vtkTextProperty>::New();
textProperty->SetFontSize(16);
textProperty->SetJustificationToCentered();

// Create the render window and interactor.
vtkSmartPointer<vtkRenderWindow> renWin =
vtkSmartPointer<vtkRenderWindow>::New();
renWin->SetWindowName("Platonic Solids");
vtkSmartPointer<vtkRenderWindowInteractor> iRen =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
iRen->SetRenderWindow(renWin);

// There are five platonic solids.
std::vector<std::string> names{"Tetrahedron", "Cube", "Octahedron",
"Icosahedron", "Dodecahedron"};
std::vector<vtkSmartPointer<vtkPlatonicSolidSource>> PlatonicSolids;
for (auto i = 0; i < names.size(); ++i)
{
PlatonicSolids.push_back(vtkSmartPointer<vtkPlatonicSolidSource>::New());
PlatonicSolids[i]->SetSolidType(i);

mappers.push_back(vtkSmartPointer<vtkPolyDataMapper>::New());
mappers[i]->SetInputConnection(PlatonicSolids[i]->GetOutputPort());
mappers[i]->SetLookupTable(lut);
mappers[i]->SetScalarRange(0, 19);

actors.push_back(vtkSmartPointer<vtkActor>::New());
actors[i]->SetMapper(mappers[i]);

textMappers.push_back(vtkSmartPointer<vtkTextMapper>::New());
textMappers[i]->SetInput(names[i].c_str());
textMappers[i]->SetTextProperty(textProperty);

textActors.push_back(vtkSmartPointer<vtkActor2D>::New());
textActors[i]->SetMapper(textMappers[i]);
textActors[i]->SetPosition(120, 16);

renderers.push_back(vtkSmartPointer<vtkRenderer>::New());

}

// Setup the viewports
auto xGridDimensions = 3;
auto yGridDimensions = 2;
auto rendererSize = 300;
renWin->SetSize(rendererSize * xGridDimensions,
rendererSize * yGridDimensions);
for (auto row = 0; row < yGridDimensions; ++row)
{
for (auto col = 0; col < xGridDimensions; ++col)
{
auto index = row * xGridDimensions + col;

// (xmin, ymin, xmax, ymax)
double viewport[4] = {
static_cast<double>(col) / xGridDimensions,
static_cast<double>(yGridDimensions - (row + 1)) / yGridDimensions,
static_cast<double>(col + 1) / xGridDimensions,
static_cast<double>(yGridDimensions - row) / yGridDimensions};
if (index > (actors.size() - 1))
{
// Add a renderer even if there is no actor.
// This makes the render window background all the same color.
vtkSmartPointer<vtkRenderer> ren = vtkSmartPointer<vtkRenderer>::New();
ren->SetBackground(colors->GetColor3d("SlateGray").GetData());
ren->SetViewport(viewport);
continue;
}

renderers[index]->SetViewport(viewport);
renderers[index]->SetBackground(
colors->GetColor3d("SlateGray").GetData());
renderers[index]->ResetCamera();
renderers[index]->GetActiveCamera()->Azimuth(4.5);
renderers[index]->GetActiveCamera()->Elevation(-18);
renderers[index]->ResetCameraClippingRange();
}
}

iRen->Initialize();
renWin->Render();
iRen->Start();

return EXIT_SUCCESS;
}


### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(PlatonicSolids)

find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkInteractionStyle
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
message("Skipping PlatonicSolids: ${VTK_NOT_FOUND_MESSAGE}") return () endif() message (STATUS "VTK_VERSION:${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE}) add_executable(PlatonicSolids MACOSX_BUNDLE PlatonicSolids.cxx ) target_link_libraries(PlatonicSolids PRIVATE${VTK_LIBRARIES})
else ()
# include all components
add_executable(PlatonicSolids MACOSX_BUNDLE PlatonicSolids.cxx )
target_link_libraries(PlatonicSolids PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS PlatonicSolids MODULES${VTK_LIBRARIES}
)
endif ()


cd PlatonicSolids/build


If VTK is installed:

cmake ..


If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..


Build the project:

make


and run it:

./PlatonicSolids


WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.